The present invention generally relates to a catalyst system and methods for making a catalyst system. The present invention also relates to apparatus, compositions, and methods for selectively removing one or more components from a fluid stream via a catalyst system.
Many conventional catalyst systems and apparatus have used catalyst materials embedded or impregnated within a support matrix to form a catalyst-matrix mixture. Such mixtures have been applied to various substrates to provide catalyst systems of the prior art. When a fluid stream is passed within, or over, such catalyst-matrix mixtures, the catalytically active materials are protected from the fluid stream by the surrounding matrix, thereby limiting the effectiveness and efficiency of the catalyst in removing components from the fluid stream. Further, such catalyst-matrix mixtures have been applied to a substrate as a paste, which tends to clog the catalyst system, thereby impeding flow of the fluid stream and causing a substantial pressure drop within the system. In addition, many prior art catalyst-matrix mixtures tend to crack and lack continuity on the substrate after the mixture has dried. Furthermore, catalyst-matrix mixtures of the prior art have been deposited as relatively thick layers, such that the mixture substantially decreases the thermal efficiency of heat exchangers of a fluid circulation system.
As can be seen, there is a need for a catalyst system for the passage of a fluid stream therethrough, the catalyst system including at least one catalytically active material, wherein the at least one catalytically active material is directly exposed to the fluid stream as the fluid stream is passed with respect to the catalyst system. There is a further need for a catalyst system which provides for the efficient removal of components from a fluid stream using a relatively small amount of catalytically active material within the system. There is also a need for a catalyst system which provides for the efficient removal of components from a fluid stream while having no substantial effect on heat exchanger efficiency or pressure drop across the system. There is a further need for a catalyst system including a thermally stable binder layer, wherein at least one catalytically active material rapidly reaches light-off temperature due to direct exposure to the fluid stream. There is also a need for a system wherein a catalyst can be applied only to specific local areas of a component where it is needed and can function, rather than having to apply the catalyst to the entire component, even though it is known that most of the applied catalyst will not be used. The present invention provides such systems using low cost materials and manufacturing processes, as will be described in enabling detail hereinbelow.